This circuit operates at a frequency of 80 KHz and modulation up to 60 kHz. The circuit is from 1980s documentation. The PUT is an uncommon component today.
When S1 is pressed, the circuit allows music to be played from an audio source on the telephone line....
This circuit was found in an Experimenters Handbook of the 1990s. The purpose of this circuit is to...
The action of this circuit, found in a 1977 amateur radio documentation, is like to a delay line....